The danger of environmental hazardous substances being contained in the parts that make up electronic and electrical devices has been indicated in recent years, and some countries or states are now regulating by law or ordinance the amounts in which these environmental hazardous substances can be contained. For instance, in the countries of the European Union, the RoHS directive (Restriction on the use of certain Hazardous Substances in electrical and electronic equipment) prohibits the use of parts containing cadmium (Cd), lead (Pb), mercury (Hg), polybrominated biphenyl (PBB), polybrominated diphenyl ether (PBDE), or hexavalent chromium (Cr(VI)) in an amount of equal to or more than 1000 ppm (100 ppm in the case of cadmium). Consequently, it is essential that manufacturers of electronic and electrical devices make sure the parts they produce do not contain environmental hazardous substances in amounts greater than allowed.
The most common way to measure the amounts in which elements are contained is to use a fluorescent X-ray analyzer that has a sensitivity of a few dozen parts per million and allows non-destructive measurement.
Procedures for using this type of analysis method to quantify the concentration of elements contained in a sample are generally well known. An example of the method of these procedures will be described through reference to FIG. 11 (see Patent Document 1).
In FIG. 11, first, in step 301, a measurement time t is set, after which measurement begins (see step 302). Then, measurement is carried out (see step 303), the measurement is terminated after the time t has elapsed (see step 304), the concentrations are calculated, and the accuracy of this calculation result (standard deviation) is calculated, which gives results for concentrations and accuracy.
The results for concentration and accuracy are displayed by an LCD or other such display means, and printed out with a printer or the like (see step 306). There are two ways to determine the accuracy of the concentration computation result here: repeating the above-mentioned procedure a number of times (from two to ten), and measuring just once as in the above procedure and then estimating from the X-ray count.
Patent Document 1: Japanese published unexamined patent application H8-43329